This study is designed to provide empirical data to address many of the unanswered questions concerning the relationship between use and distribution of drugs and violent behavior. The research will assess the applicability of three conceptual models of this relationship. These are the psychopharmocological, the economic-compulsive and the systemic. The psychopharmocological model suggests that as a result of ingesting specific substances, persons may exhibit irrational and/or violent behavior. The economically-compulsive model suggests that drug users may engage in violent crime in order to support costly drug use. The systemic model refers to the traditionally aggressive patterns of interaction within the illicit drug market. The project will test two hypotheses: (1) that drug users who are engaged in drug distribution are more likely to be victims of perpetrators of violence than drug users not so employed and (2) that those drug users who most often engage in violent behavior are most likely to be the victims of violence. A major tenet of the proposed research is that the effects of drug/violence interrelationships may be the most critical health issue for which rigorously collected data of broad scope is currently unavailable. A cross-sectional sample of 150 drug users will be interviewed on a weekly basis in their own behavioral milieu. A sub-sample of this group will be selected for longitudinal follow-up. Life history information will be gathered from all subjects. Focused interviews will be undertaken around specific violent episodes. The project will seek to determine the nature, scope, and meaning of violent behavior with the context of the world of drug use and distribution. Further, a structural analysis of drug dealing operations will be undertaken with special emphasis on the association of violence with drug trafficking. It is anticipated that the data base to be established will have important policy implications in the areas of drug treatment and prevention, law enforcement, criminal sentencing anc corrections.